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Bat walk in Windmill Gardens

Image: Nick Weedon

Jean Kerrigan reports on the first bat walk in Windmill Gardens

The first bat walk organised by FoWG in Windmill Gardens on Thursday 24 July proved a success. It was a warm summer evening as we gathered at the gate to the park at 9pm. Dr Iain Boulton from Lambeth Council’s Communities & Education parks project introduced our group of Friends, local residents, and young people who had found out about the walk at the Lambeth Country Show, to the mysteries of using bat detectors.

All bats in the UK are protected by law. We learned that British bats are insect eaters devouring up to 3,000 insects a night. They can travel up to four or five miles in their search for food.

Bats come out after sunset, and because of their poor eyesight they seek out their food supply by emitting ultrasound bursts that bounce back, directing them to a food source.

These sounds cannot be heard by humans - hence the need for the bat detectors. The handheld detectors emit white sound, and when they pick up the bats’ ultrasound bursts – described by Iain as a series of "lip smacks and kissing sounds" – the detector converts them to sound that we can hear.

It took several circuits of the park and quite a while for us to pick up the echolocation calls on the bat detectors from two or three common pipistrelle bats, but in the end we did. Some of us were lucky enough to catch sight of the small bats flying into and around the lime trees in the park.

It proved an interesting evening, and the results will be sent on by Iain to the London Bat Group, as sighting common pipistrelle bats in Windmill Gardens fills in an existing data gap.

We plan to hold another evening bat walk in Windmill Gardens during the second week in September. Look out for details in our e-newsletter.